The present invention relates in general to providing communications services, and, more particularly, to a method and system for using dynamic Internet protocol (IP) address assignment and dynamic DNS updates to provide wireless data and voice services to subscribers using mobile terminals, for example via the Internet.
Wireless or xe2x80x9cmobilexe2x80x9d telecommunications are well known for enabling subscribers to have immediate access to voice and data services while roaming large geographic areas. Presently, cellular and personal communication services (PCS) telephones are the most common form of mobile unit for wireless communications. Cellular/PCS telephones operate in cooperation with known wireless networks which include cell sites having controllers and radio transceivers, mobile telephone switching centers, and, of course, mobile units, i.e., portable telephones or handsets. Mobile telephone switching centers are known to those skilled in the art to comprise digital telephone exchanges which switch interconnections between telephony signaling networks and the cell sites for wireline-to-mobile and mobile-to-wireline connections and also for mobile-to-mobile connections. The mobile telephone switching centers also process mobile unit status data received from cell site controllers, switch calls between cells, process diagnostic information, and compile billing data.
Each subscriber to a wireless service is assigned to a wireless home network. The home network stores subscription information for the subscriber along with unique identification information, typically a number, for the mobile unit used by the subscriber. The subscriber is typically able to place and receive wireless calls anywhere within the home network""s service area. Most subscribers are also able to place and receive wireless calls while roaming outside the service areas of their home networks since most wireless service providers either have service coverage in other areas or they have established roaming agreements with other service providers. Under roaming agreements, subscribers of a service provider that is a party to an agreement with other service providers can access networks of the other service providers in accordance with the terms of the agreement. Cellular/PCS networks accessed by subscribers roaming out of their wireless home networks are known to those skilled in the art as wireless visited networks. From the subscriber""s perspective, a visited network can be either owned and operated by the same service provider who provides services in the home network, or by a different service provider with whom a roaming agreement exists.
In operation, when the mobile telephone switching center in one""s home network receives a call from the telephony signaling network and the call is directed to a mobile device user registered with the home network, the mobile telephone switching center deciphers the received telephone number and alerts the controllers at the cell sites to page the corresponding mobile user. Similarly, when a mobile device user registered with the home network places a call in the home network""s service area, the mobile telephone switching center in the home network receives the corresponding called number from the cell site controller and transmits the called number to the telephony signaling network.
On the other hand, when a mobile device user registered with the home network places a call outside the home network""s service area, the mobile telephone switching center in the visited network communicates with the home network to authenticate the user and determine whether the mobile device user has authority to roam and to place the call. If authentication is confirmed by the home network, the mobile telephone switching center in the visited network accepts the called number from the cell site controller and transmits the called number to the telephony signaling network.
Wireless networks can also provide peer-to-peer and mobile server packet data operations. FIG. 1 illustrates a communications system 10 for peer-to-peer communication of packet data users and mobile servers. The communications system 10 comprises a plurality of wireless networks 11-13 coupled to an IP network 14, such as the Internet, by respective routers 15-17. A variety of communications devices may access the IP network 14 via the different cellular/PCS networks 11-13. As illustrated in FIG. 1, a mobile server 18 (host name: mobile-www.xyz.com) communicates with the IP network 14 via the first cellular/PCS network 11, a first voice/data mobile device 19, such as a smart phone, laptop, palm device, (host name: YourName.abc.com) communicates with the IP network 14 via the second cellular/PCS network 12 and a second voice/data mobile device 20 communicates with the IP network 14 via the third cellular/PCS network 13. A fixed host 21 communicates with the IP network 14 via a standard wireline connection.
Peer-to-peer communications include packet multimedia interactions between the fixed host 21 and the mobile devices 19, 20 and between the mobile devices 19, 20 themselves. Mobile server and client packet multimedia interactions are possible between the fixed host 21 and the mobile server 18 and between the mobile devices 19, 20 and the mobile server 18.
One of the most convenient means of denoting the destination end point of another party in either peer-to-peer or client-server communications is the use of host name notation. Thus, a fixed or mobile client can communicate with a mobile server by simply referring to the mobile server""s host name, e.g., mobile-www.xyz.com. Similarly, a fixed or mobile peer can engage in an IP-telephony conversation with another mobile peer by simply referring to the other mobile peer""s host name, e.g., YourName.abc.com. In each case, a Domain Name System (DNS) server associated with the network to which the host name is registered is responsible for translating the symbolic host name to its corresponding IP address which comprises four numbers separated by periods, e.g., 35.1.1.1, which is needed for standard IP packet routing over the IP network. Normally, the host name is registered to the home network to which the mobile device user is registered.
The IP address associated with a particular host name is typically assigned on a per session basis with the assigned IP address being reclaimed once the session ends. Such an assignment of IP addresses is known to those skilled in the art as dynamic IP address assignment. For example, as shown in FIG. 2, a wireless home network 24 could assign a session IP address dynamically to a mobile device user 26 using a mobile device 28 to communicate with the home network 24 and update the host name-to-IP address association in its DNS server 30 to allow peer-to-peer communication between the mobile device 28 and a fixed computer host 32 interfacing via an IP network 34. The home network 24 is coupled to the IP network 34 via a router 36. As the IP address assigned by the home network 24 and the host name are both registered with the home network 24, all DNS queries and packet transfers between the computer host 32 and the mobile device 28 are routed through the home network 24. Both forward and reverse DNS lookups about the mobile device 28 are resolvable by the DNS 30 when the mobile device 28 is connected to the IP network 34 through its home network 24. A forward DNS lookup is a request for the IP address associated with a particular host name while a reverse DNS lookup is a request for the host name associated with a particular IP address.
Referring now to FIG. 3, with like reference numerals referring to like components, the wireless home network 24 could also assign a dynamic address to the mobile device 28 connected through a visited network 38 and update the host name-to-IP address association in its DNS server 30 to allow peer-to-peer communications between the computer host 32 and the mobile device 28. The visited network 38 is connected to the IP network 34 via a router 40 and may be able to communicate with the home network 24 via a telephony signaling network 42. However, for such operation an IP tunnel 44 is formed between the router 36 of the home network 24 and the router 40 of the visited network 38 so that all DNS queries and standard IP packets destined to the IP address assigned by the home network 24 can be routed through the IP network 34 to the router 36 of the home network 24, the tunnel 44 and the router 40 of the visited network 38 to the mobile device 28. The tunnel 44 basically redirects the IP packets to the mobile device 28 over the IP network 34. While the tunnel 44 addresses the issue of mobility, it introduces extra end-to-end network latency or delay that could be long with possible severe impact on real-time applications like IP telephony.
One way to avoid the tunnel 44 and thus eliminate unnecessary network delay is to assign the roaming mobile device 28 an IP address local to the visited network 38. In this situation, a dynamic IP address local to the visited network 38 is assigned to the mobile device 28, and a DNS server 45 in the visited network 38 associates the host name of the mobile device 28 which is registered with the home network 24 with the local IP address which is registered with the visited network 38. Such an arrangement avoids the creation of the tunnel 44 and the inherent network delays. However, forward DNS lookup will fail because all queries concerning the IP address of the host name are transmitted to the home network that xe2x80x9cownsxe2x80x9d the domain name associated with the host name and there is no association between the host name and the IP address in the DNS server 30 of the home network 24. As a result of this forward DNS lookup failure, peer-to-peer and mobile server communications via host names cannot take place.
Accordingly, there is a need for a method and system for providing data and voice services to subscribers at mobile terminals that avoids DNS lookup failures and does not introduce additional unnecessary network delays. There is also a need for such a method and system that functions in a secure manner using existing infrastructure. There is a further need for such a method and system that is relatively easy to implement and cost effective.
The present invention meets these needs by providing a method and communications system providing data and voice services to subscribers at mobile terminals using dynamic IP address assignment. A visited network dynamically assigns one of its IP addresses to a mobile terminal accessing the visited network as a session IP address. The visited network transmits the assigned IP address to the home network of the mobile terminal over a private network. The home network associates the assigned IP address from the visited network with the host name of the mobile terminal in its DNS server and sends the host name to the visited network, although the visited network may already have received the host name from the mobile terminal. The visited network associates the host name of the mobile terminal with the assigned IP address in its DNS server. Upon termination of the data call by the mobile terminal, the visited network disassociates the assigned IP address with the host name in its DNS server and instructs the home network to do the same.
According to a first aspect of the present invention, a method of providing dynamic Internet protocol (IP) address assignment to a mobile terminal having a predetermined host name that is registered with a home network comprises assigning an IP address to the mobile terminal by a visited network accessed by the mobile terminal. The IP address is transmitted from the visited network to the home network using a private network. The host name of the mobile terminal is associated with the IP address assigned by the visited network in the home network.
The step of assigning an IP address to the host name of the mobile terminal by a visited network accessed by the mobile terminal may comprise accessing the visited network by the mobile terminal, establishing a communications link between the visited network and the home network using the private network, transmitting identification information of the mobile terminal from the visited network to the home network using the private network, authenticating the mobile terminal by the home network in response to the identification information, transmitting subscription information and authentication confirmation for the mobile terminal from the home network to the visited network using the private network, and assigning the IP address to the mobile terminal by the visited network in response to the subscription information and authentication information. The step of assigning the IP address to the mobile terminal by the visited network in response to the subscription information and authentication information may comprise requesting the IP address from a dynamic host configuration protocol (DHCP) server of the visited network, and associating the IP address with the host name of the mobile terminal registered with the home network in a domain name system (DNS) server in the visited network. The step of associating the host name of the mobile terminal with the IP address assigned by the visited network in the home network is carried out in a DNS server in the home network.
Preferably, the private network is a telephony signaling network, such as the American National Standards Institute 41 (ANSI-41) network, the Global System for Mobile Communications Mobile Application Part (GSM-MAP) network, or a combination of both networks. The method may further comprise the step of disassociating the IP address from the mobile terminal in the visited network and in the home network upon termination of access of the visited network by the mobile terminal. The mobile terminal may comprise a mobile server or a mobile voice and data device, such as a smart phone, laptop or Palm device. The method may further comprise the step of transmitting the host name of the mobile terminal from the mobile terminal or the home network to the visited network.
According to another aspect of the present invention, a communications system for providing voice and data services to mobile subscribers using mobile terminals is provided. The system comprises a home network and a visited network. The home network comprises a home location register (HLR) for storing and providing subscription information, identification information and authentication information of the mobile terminals registered with the home network, and a home DNS server mapping host names registered with the home network to the IP addresses assigned to the mobile terminals. The visited network comprises a visitors location register (VLR) in communication with the HLR in the home network by a private network, such as a telephony signaling network, a visited DNS server mapping host names to IP addresses, a visited dynamic host configuration protocol (DHCP) server having a plurality of IP addresses registered with the visited network, and a router providing access to an IP network. The visited network is configured to assign IP addresses registered with the visited network to mobile terminals accessing the visited network thereby providing the mobile terminals access to the IP network via the router. The visited network is further configured to transmit IP addresses assigned to the mobile terminals to the HLR using the private network. The home network is configured to associate the assigned IP addresses with corresponding host names of the mobile terminals in the home DNS server.
The visited network is preferably configured to assign IP addresses registered with the visited network to the mobile terminals accessing the visited network upon receipt of subscription information and authentication information from the HLR indicating that the mobile terminals have authority to access the visited network. The visited network may be further configured to associate the assigned IP addresses with the host names of the mobile terminals in the visited DNS server. The visited network is preferably configured to disassociate the assigned IP addresses from the host names of the mobile terminals in the visited DNS server upon termination of access of the visited network by the mobile terminals.
The VLR may be configured to instruct the HLR to disassociate the assigned IP addresses from the host names of the mobile terminals in the home DNS server upon termination of access of the visited network by the mobile terminals. The private network preferably comprises a telephony signaling network. Preferably, at least one of the mobile terminals is a mobile voice and data telephone or a mobile server. The system may further comprise a plurality of the visited networks. The mobile terminals may be configured to transmit the host name of the mobile terminals to the visited network. Alternatively, the HLR may be configured to transmit the host names of the mobile terminals to the visited network.
Accordingly, it is an object of the present invention to provide a method and system for providing data and voice services to subscribers at mobile terminals that avoid DNS lookup failures and does not introduce network delays. It is another object of the present invention to provide such a method and system that function in a secure manner using existing infrastructure. It is yet another object of the present invention to provide such a method and system that are relatively easy to implement and are cost effective.